Hybrid electric vehicles commonly use both the electric and fossil fuel drive systems to minimize fuel consumption. As a result, controlling the hybrid vehicle drive system often includes making some determination of how best to expend electrical power along with (or instead of) burning fossil fuel in the engine. In some circumstances it may be advantageous to favor the use of electrical power to a greater degree where in other circumstances the best fuel economy may be achieved by burning more fuel in the engine and using less electrical power in the electric motor generator. Determining this balance may be difficult and is often counterintuitive because numerous factors may be involved in determining the best fuel economy such as the fuel efficiency of the engine, the quantity and maximum transfer rate of electrical energy available, losses incurred in the transfer of electrical energy at various power levels, as well as the speed of the vehicle, its weight, and numerous other related factors.